PYREX® Square Glass Media Storage Bottles manufactured by Corning are made from PYREX borosilicate glass for chemical and thermal resistance. Square bottles are easier to handle, require less space (13% to 20%) on the shelf or in the autoclave and are ideal for mixing, sampling, and storage. Square bottles have white enamel graduations, large marking spot and a glass ridge molded into the bottle to indicate full capacity. Square bottles also have linerless, one-piece, autoclavable, orange, polypropylene plug seal cap with drip-free pouring ring.